Also on Friday, AT&T said it had sold 200,000 iPhone 4S smartphones in the first 12 hours of availability, and boasted of "extraordinary demand" that made the day "the most successful iPhone launch we've ever had."

As of Sunday, AT&T cited high demand when it told customers ordering the iPhone 4S through its website that their phones would ship in 21 to 28 days.

"To get iPhone 4S as soon as October 14, AT&T retail stores will have inventory available for eligible customers while supplies last," a message stated during the ordering process.

Also on Sunday, Verizon's site stated a delivery date of Oct. 21., while Sprint reported it had sold out of the lowest-priced 16GB iPhone 4S. Supplies of the more expensive 32GB and 64GB were still available from Sprint for delivery Oct. 14 or Oct. 15.